C-reactive protein (CRP) is the prototypic marker of inflammation. Numerous studies in healthy volunteers have confirmed that CRP predicts cardiovascular events and is a risk marker. Also recent studies support a role for CRP in atherogenesis. CRP has been shown to induce cell adhesion molecules, chemokines and endothelin-1 in endothelial cells (EC) and reactive oxygen species, cytokines and tissue factor in monocytes. We have recently shown that CRP directly inhibits the expression and bioactivity of endothelial nitric-oxide synthase (eNOS) in human aortic endothelial cells and augments monocyte-endothelial cell adhesion. Furthermore we have also shown that CRP inhibits prostacyclin release and stimulates PAl-1 release from human aortic EC. Thus the central hypothesis of this proposal is that CRP promotes atherothrombosis via effects on both endothelial cells and monocytes. In Specific Aim 1 we will examine the mechanisms via which CRP decreases eNOS expression and activity in human aortic and coronary artery endothelial cells. In Specific Aim 2, we will test the effect of CRP on monocyte endothelial cell adhesion under both static and defined shear flow conditions and will delineate the molecular mechanisms involved. In Specific Aim 3 we will determine if the processing of CRP is receptor mediated and if this accounts for its biological effects. Finally in Specific Aim 4, we will use Sprague-Dawley and Zucker rats to confirm our findings in vivo. We will test the effect of CRP in vivo on endothelial vasoreactivity, on low density lipoprotein retention and on macrophage biology including cellular adhesion molecule expression, secretion of tissue factor, matrix metalloproteinases and foam cell formation. Thus, these studies will clearly provide us with further scientific evidence in support of the role of CRP in atherothrombosis. [unreadable] [unreadable]